Experimental investigation of square dissipative soliton generation and propagation

We have experimentally investigated the generation and propagation of square dissipative solitons emitted from an erbium-doped fiber laser with large normal cavity dispersion. The square pulse exhibits an approximately Gaussian spectral profile and large frequency chirp on its edges. When the square pulse propagates through a segment of single-mode fiber (SMF), it can be shaped to a Gaussian pulse and the corresponding spectrum will have a redshift with a prolonged wing on the longer wavelength. Our experiments show that the pulse evolution in the SMF is determined by the combined effects of the fiber dispersion, intrapulse Raman scattering, and the pulse initial chirps.